Should I steer clear of these "fast-growing" shade trees?

timsondrupMay 12, 2014

I just planted the following fast-growing shade trees in my front and back yards: Royal Empress (Paulownia elongata), Hybrid Poplar (Populus), and Eucalyptus (Eucalyptus cinerea)

After discovering that the Eucalyptus tree is prone to breaking and has shallow roots, I decided it would probably be best to go with a different tree. Upon doing research on the other two trees, I found that the hybrid poplar (or any tree of the Populus variety) is not recommended. I was't able to find any downsides to the Royal Empress.

I live in Northern Utah, right along the bench. Any advice offered will be considered. Thanks!

Generaly fast growing trees are going to be weaker than the slower growing trees. What some people do is plant both fast and slow growing trees. The fast trees give shade sooner. Then as the slower stronger trees catch up and provide shade, the faster weak trees are removed before they become a hazard.

So you could leave them in for now with the plan to remove them at some point, and plant your prefered better suited trees.

I would recommend staying away from fast growing trees. Especially what I consider to be weed trees... most varieties of willow trees, box elder, poplar. One fairly quick growing shade tree that I would highly recommend in any soil type is green ash.

I'm growing eucalyptus gunnii and eucalyptus parvula here in Ogden. I intend to cut them down to about 7' for the first 2 or 3 winters and protect them until the trunks get a bit thicker. I don't want them to freeze dry in a winter wind.

Before I lived here I planted a eucalyptus glauscesens and neglecta at my parents place and they survived unprotected for a few years although they would lose many of there leaves and die back a bit in winter. Unfortunately someone well meaning but ignorant took them out one spring when they were looking a bit bare.

As for paulownia, they can be very messy and I wouldn't plant it unless you have a huge yard, unless you want to keep it small. If you top it off at 12' or so every year or two it will grow very different. It won't bloom but the leaves will grow about 2' in diameter.

The faster trees grow, the shorter their lifespan and weaker they are (at least regarding broadleaf trees....- conifers are a law unto themselves)...but, I do have to wonder why you wanted 3 of them. The hybrid poplars (and, as I garden in a poplar plantation, I know of what I speak) have very little charm to be honest - the timber is weak and without much intrinsic interest, the canopy is negligible (so useless as a shade tree), they have no autumn colouring, take ages to leaf up and are already bare. They sucker.
Eucalypts....I have rarely seen a well-grown gum without severe leaning issues.....so unless you have added in the extra space a 45degree angle will add (Like a gigantic apple cordon....without the benefits), take it out....
Paulownias....are you growing for biomass? I can see few advantages to growing this monster....but will agree that whilst it has few pluses, it certainly does not have the screaming negatives of the former pair of yahoos. I am biassed against this tree since my dimwit neighbour has planted one in her garden....which is 5metres wide, right next door to my 5m wide home garden...it is only 3 years old and is taking half of her alloted space....the chainsaw will be out the second it overgrows my wall).
I don't really hang out here ever so feel free to be blunt and truthful....why, with a hundred better, nicer, more useful and appropriate trees to select, would you go for a couple of thugs. Even the rampant poplar will hang around for 80 years...so these charmless blights are going to be there, huge and visible for a lifetime. Unless the speed of their growing is your only criteria (in which case, top choices), I cannot imagine why you would impose such dullards on your landscape.

I can't imagine any of the eucalypts being very successful for you as any sort of a shade tree. Even the very hardy species - E. gunnii, cinerea, etc - are frequently knocked down to the roots in the odd winter around here. They survive, but mostly as shrubby specimens. Very unusual to see a full sized tree even in my very mild climate.

Why not a nice red maple? Or Freeman or Shantung maple? Growth rate is moderate, will get to a decent size and will provide some fall color as well. Or Liriodendron tulipifera, which grows quite rapidly in suitable soils.

I should have added, if you are growing eucs here please be forewarned that you are seriously pushing the envelope. If you realize there is a strong possibility they will completely die without protection and that doesn't bother you than I say go for it.

Personally I love pushing the envelope. I do it here and I did it in western Washington. Sometimes it's complete failure. Sometimes it's rousing and surprising success. Sometimes you just get to enjoy a unique plant for the area for a few years before it succumbs.

You'll have to listen to the occasional self-appointed world plant cop though who wants to tell everyone what they should or shouldn't plant. I don't give those types a second thought. It's my yard and as long as I'm not planting anything invasive then it's none of their concern.